JP2006059673A - Fuel cell driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell driving device capable of continuously operating without causing clogging. <P>SOLUTION: The fuel cell driving device is equipped with a filter part 2B which physically or chemically filters air when clean air is supplied to a fuel cell, a plurality of filters 4A, 4B filtering by physical adsorption air filtered in the filter part 2B, switching devices 11, 12 switching the filter 4A used at present to other filter 4C, a detector 13 detecting the flow rate of air installed in the later part of the filter part 2B, detectors 14, 15 detecting the flow rate of air installed in later parts of the plurality of filters 4A, 4B, and a control means 16 outputting an indication signal replacing the filter part 2B when the flow rate of air detected with the detectors 13, 14, 15 is less than a reference value, or outputting a switching signal switching the filter 4A used at present to other preliminary filter 4B. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell drive device that can be used in various environments.

  Various chemical batteries are used in all fields of consumer and industrial use. For example, primary batteries such as alkaline batteries and manganese batteries are often used in watches, cameras, and portable devices. Secondary batteries such as nickel cadmium storage batteries and lithium ion batteries are used in digital cameras, portable information terminals, and the like.

  On the other hand, from the viewpoint of the global environment, environmental problems with respect to disposal after use of the above-described batteries have become apparent. Various systems using a fuel cell having extremely high energy conversion efficiency have been proposed in consideration of this environmental problem.

As this fuel cell, there is one described in Patent Document 1.
That is, the fuel cell described in Patent Document 1 has a configuration in which both ends of a proton conducting portion made of a polymer electrolyte are sandwiched between positive and negative electrodes in which a catalyst is dispersed in an electrode. In the positive electrode, for example, platinum serving as a catalyst is dispersed in carbon fiber, and protons that have passed through the proton conducting portion on the positive electrode react with oxygen in the air covering the positive electrode to generate water. It has a structure. On the negative electrode, for example, platinum as a catalyst is dispersed in a carbon material, and the methanol fuel containing water passing over the negative electrode is decomposed into hydrogen, and further emits electrons to become protons. Conducted to. The battery configuration in which these are combined has a U-shaped exterior covering from the negative electrode to the side surface of the positive electrode, and methanol containing water is introduced into the upper surface.

  Then, methanol containing water is supplied from the fuel supply port to the fuel chamber, and protons generated on the negative electrode side move to the positive electrode side together with protons dissociated at the proton conducting portion, and oxygen or oxygen is generated on the surface of the positive electrode. The electromotive force is taken out by reacting with air.

In this fuel cell, the electrode and the catalyst are devised so that hydrogen can be obtained directly from water and methanol on the negative electrode, but in order to obtain hydrogen from water and methanol, a device called a reformer is installed in front of the negative electrode. There is also a configuration arranged in the above.
This fuel cell is being considered for use in portable consumer electronics products such as notebook computers and camera-integrated video. As a place where this fuel cell is used, a bad environment such as a beach or a hot spring can be considered.
When used in such a poor environment, it can be considered that dust and dirt contained in the air adhere to and cover the carbon fibers of the negative electrode of the fuel cell, thereby suppressing the generation of water.

In addition, hydrogen sulfide contained in the air and sodium chloride fine particles contained in the air in the vicinity of the coast poison the platinum catalyst of the negative electrode, which may reduce the action of synthesizing water from hydrogen and oxygen. .
As a result, there arises a problem that the electromotive force is lowered and the fuel cell does not operate.

In order to solve this, there is one described in Patent Document 2.
In the fuel cell described in Patent Document 2, the fuel cell main body having a structure in which a solid polymer electrolyte is sandwiched between an air electrode and a fuel electrode is held by a separator for each battery cell, and air supplied to each battery cell A detector that turns on an insufficient flow rate lamp indicating that the air filter is clogged when the value of the flow sensor for supplying fuel to the fuel cell falls below a predetermined amount with respect to hydrogen is provided.
Japanese Patent Laid-Open No. 2002-63917 JP 2000-46587 A

  However, since the cause of the clogging of the air filter cannot be determined, even if the fuel cell can be operated by replacing the air filter, a countermeasure for dealing with the cause of the clogging is taken. I couldn't pick it. That is, when using the fuel cell in hot springs, the seaside or near the road, physical things such as dust, oil particles, cotton dust, feathers, sand dust, hydrogen sulfide gas, sodium chloride fine particles, sulfur oxides, Since it was not known whether clogging occurred due to any one of chemical substances such as nitrogen oxides and particulate matter, effective countermeasures could not be taken. For this reason, the fuel cell must be used with anxiety about when it will stop.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fuel cell driving device that can be always operated without causing clogging.

According to a first aspect of the present invention, a fuel cell that generates an electromotive force by a chemical reaction between hydrogen and oxygen produced by a chemical reaction of fuel is required to always cause the chemical reaction regardless of the external environment. In a fuel cell driving apparatus that stably supplies air used by separating oxygen, a first filter unit having a filter for physically or chemically filtering the air, and the air filtered by a filter of the first filter unit A second filter unit having a plurality of filters for physical adsorption filtration, a switch for switching a filter used among the plurality of second filter units to a spare filter, the first filter unit and the second filter unit When the flow rate of air that is provided between the filter portions and passes through the first filter portion is detected and the flow rate of the air is equal to or less than a reference value, the first A first detector for displaying an instruction signal for exchanging the filter unit; and a second stage of the second filter unit that detects the flow rate of air passing through the second filter unit and the flow rate of the air is below a reference value When the second detector that displays a switching signal to be switched to the preliminary filter of the second filter unit and the flow rate of the air detected by the first detector is below a reference, An instruction signal for exchanging the first filter unit is output to the first detector, and the flow rate of the air detected by the second detector is less than a reference, or the acidity and alkalinity of the air are out of reference values. If the integrated flow rate of air is equal to or greater than a certain amount, the second detector outputs a switching signal for switching the filter used in the second filter unit to the spare filter. And a fuel cell drive device characterized by comprising a control means.
According to a second aspect of the present invention, there is provided the fuel cell drive device according to claim 1, wherein the plurality of filters of the second filter section are filters that perform physical adsorption filtration that can be regenerated by heating.

  According to the present invention, a second filter having a first filter portion having a filter for physically or chemically filtering air and a plurality of filters for physically adsorbing and filtering the air filtered by the filter of the first filter portion. A switching device that switches a filter used in the plurality of second filter units to a spare filter, and the first filter unit is provided between the first filter unit and the second filter unit. A first detector for detecting a flow rate of air passing through the first filter unit and displaying an instruction signal for replacing the first filter unit when the flow rate of the air is equal to or less than a reference value; And detecting a flow rate of air passing through the second filter unit and switching to a spare filter of the second filter unit when the air flow rate is less than a reference value. When the flow rate of the air detected by the second detector displaying the switching signal and the first detector is below a reference, an instruction signal for exchanging the first filter unit is sent to the first detector. The flow rate of the air detected by the second detector is less than the reference, the acidity and alkalinity of the air are out of the reference values, or the integrated flow rate of the air is a certain amount or more In this case, since the second detector has a control means for outputting a switching signal for switching the filter used in the second filter unit to the preliminary filter to the second detector, without causing clogging, A fuel cell drive device that can be operated at all times is obtained.

Hereinafter, a fuel cell driving apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic diagram showing a fuel cell driving apparatus according to an embodiment of the present invention.
2A and 2B show the configuration of the fuel cell, where FIG. 2A is a perspective view and FIG. 2B is a cross-sectional view.
FIG. 3 is a diagram showing a combination of filter units used in the fuel cell driving device.
FIG. 4 is a schematic diagram showing a modification of the embodiment of the present invention.

  As shown in FIG. 1, a fuel cell driving device 1 according to an embodiment of the present invention includes a cartridge 2A containing methanol and a filter 2B that removes dust and the like from a flowing air by chemical filtration and chemical substances by chemical adsorption filtration. The filter unit 2 is connected to the filter unit 2 via the pipe P1 and connected to the pump 3 for sending out the air physically or chemically adsorbed and filtered by the filter 2B of the filter unit 2, and the pump 3 and the pipe P2. A plurality of filters 4A and 4B for removing volatile substances by physical adsorption filtration from the physical or chemical adsorption filtered air sent out by the pump 3, and volatile substances physically adsorbed by each filter are heated to evaporate. Connected to the filter unit 4 having the heaters 4C and 4D, the filter unit 2 and the pipe P3. A fluid pump 5 for feeding methanol supplied from 2A, a reformer 6 connected to the fluid pump 5 via a pipe P4 and chemically reacting the methanol sent from the fluid pump 5 to generate hydrogen gas; It is caused by an electrochemical reaction from hydrogen gas generated by the reformer 6 by being connected to the mass device 6 and the pipe P5 and air that has been physically adsorbed and filtered by the filter section 4 by being connected to the filter section 4 and the pipe P6. And a fuel cell 7 for generating electric power.

Further, the fuel cell 7 includes a load resistor 8 connected between an air electrode and a fuel electrode, which will be described later, and a load resistor 8 and air, for measuring an electromotive force generated by an electrochemical reaction between hydrogen and oxygen in the air. A current detector 9 for detecting an output current is connected between the electrodes or the fuel electrode, and has an exhaust port 10 for discharging water generated by the electrochemical reaction.
Furthermore, a switch 11 for selecting the filters 4A and 4B of the filter unit 4 is connected in the middle of the pipe P6. A switch 12 for selecting the filters 4A and 4B in the filter unit 4 is connected in the middle of the pipe P2.

Further, a detector 13 for detecting the flow rate of air physically filtered and chemically adsorbed and filtered by the filter 2B and displaying an instruction signal for replacing the filter 2B when the air flow rate is equal to or less than a reference value in the pipe P2. Is connected.
On the outlet side of the filters 4A and 4B of the filter unit 4, the flow rate of the air physically filtered by the filters 4A and 4B is detected, respectively, and the air flow rate is below the standard, or the acidity and alkalinity of the air are the reference values. 14 and 15 for displaying a switching signal for switching the filter 4A used in the filter unit 4 to another spare filter 4B when the integrated flow rate of air is equal to or greater than a certain amount. It is connected.

  Furthermore, an instruction signal for controlling the pump 3 and the fluid pump 5 based on the current value of the current detector 9 and exchanging the filter 2B when the flow rate of air detected by the detector 13 is below the reference. Is output to the detector 13 and the air flow rate detected by the detectors 14 and 15 is below the reference value, the acidity and alkalinity of the air are out of the reference value, or the integrated air flow rate is above a certain amount. In some cases, a control circuit 16 is provided that outputs to the detector 14 a switching signal for switching the filter 4A used in the filter unit 4 to another spare filter 4B.

  As shown in FIGS. 2A and 2B, the fuel cell 7 includes an electrolyte 18 having a catalyst layer 17 formed on both sides, an air electrode 19 and a fuel electrode 20 sandwiching the electrolyte 18, and an air electrode. 19 and a pair of separators 21, 21 provided on the opposite side of the fuel electrode 20 from the electrolyte 18. An air passage through which air flows is formed between the separator 21 and the air electrode 19, and a hydrogen gas passage through which hydrogen gas flows is formed between the separator 21 and the fuel electrode 20. . In this case, the air electrode 19 is a positive electrode, and the fuel electrode 20 is a negative electrode. The load resistor 8 and the current detector 9 are connected in series between the air electrode 19 and the fuel electrode 20. The air electrode 19 and the fuel electrode 20 side of the separator 21 are made of dense graphite, and the air electrode 19 and the fuel electrode 20 are made of a porous material.

As shown in FIG. 3, the filter 2 </ b> B includes a physical filter M and a chemical adsorption filter N.
The physical filter M is made of a mesh-like sheet and captures a substance larger than the mesh of this sheet. It is called a pulp filter, a paper filter made by knitting or rinsing so-called cellulose fibers, or a non-woven fabric filter made of woven fabric such as polyester fiber, polyethylene fiber, polyamide fiber, polyimide fiber, etc. is there.

The chemical adsorption filter N is adsorbed by neutralization or the like using a chemical reaction with a chemical substance. The adsorption energy is an order of magnitude larger than that of physical adsorption, and prevents the catalyst layer 17 from deteriorating. Is provided.
When calcium hydroxide particles are used in the chemical adsorption filter N, it is weakly alkaline, and therefore suitable for filtering acidic substances such as sulfur oxides and nitrogen oxides contained in automobile exhaust gas. This is because an acidic substance is neutralized and removed with an alkaline filter, so that the substance can be efficiently removed.

  For such a chemical adsorption filter, it is also preferable to use orthophosphoric acid which is made of an acidic substance and adsorbs ammonia gas which is an alkaline substance. Since orthophosphoric acid adsorbs moisture and becomes syrup, it can be easily dissolved and neutralized and adsorbed by an acidic substance, and thus is suitable for the filtering substance of the present invention. The chemical adsorption filter N also includes a chemical adsorption filter using alumina. By using this chemical adsorption filter N, because alumina acts as a harmful substance and chemically changes to aluminum hydroxide or the like, the efficiency of the air electrode 19 is reduced or the catalyst layer 17 is poisoned. Can be prevented.

  These physical filters M and chemical adsorption filters N have common points in that their performance is irreversible. The filter fulfills its function by retaining unnecessary components in the substance entering through the suction port. In the physical filter M, the filtration function is caused by clogging of unnecessary substances in the filtration mesh, but the unnecessary substances clogged in the mesh cannot be easily removed. It is not easy to restore the filter, and the filter function is generally restored by replacing it with a new filter. Also in the chemical adsorption filter N, when harmful substances such as acidic and alkaline are inhaled, the chemical substances in the filter filter the harmful substances by chemically reacting with the harmful substances such as neutralization. Since the chemically reacted substance does not easily return to its original state, it does not recover its performance and is irreversible.

Further, the physical adsorption filter O of the filters 4A and 4B in the filter unit 4 is made of a physical adsorption material, is made of a material having a predetermined mesh, and is physically filtered with the physical adsorption material to be taken in and filtered. is there. The difference from the physical filter M described above is that it has a function of adsorbing and filtering a substance having a finer size than the mesh of the filter on the mesh surface.
When the physical adsorption filter O loses the adsorption function, it can be made reusable by heating. The physical adsorption filter O is not limited to a mesh shape, and may have a shape in which a large number of fine adsorption holes are formed on the surface, such as activated carbon.

  Filters used in this physical adsorption filter O include graphite or carbon black particles packed in activated carbon such as activated carbon, viscous materials such as kaolinite and montmorillonite, which are unglazed at a temperature of several hundred degrees and then pulverized. Particles packed in a pipe are used. Further, silica gel made of silicon dioxide, activated alumina obtained by heating aluminum hydroxide, and synthetic zeolite which is an oxidized compound of silicon, aluminum and metal can also be used. Furthermore, an adsorption plate made of a plastic material having fine protrusions using a configuration in which fine particles are adsorbed by static electricity generated in the fluid can be used. Substances that can be removed by such a filter are effective for removing moisture such as water vapor and moisture, organic solvents such as toluene, benzine and gasoline, and odorous components such as acetates and acrylates. When these components are adsorbed on the air electrode, it is desirable to remove them as much as possible to cover the electrode surface and reduce the reaction area of the electrode.

The regeneration method of the filter in which physical adsorption has occurred is based on the following principle. In the physical adsorption, when the Brownian motion of the adsorbed molecule becomes active and the Brownian momentum exceeds the adsorptive power, the adsorption becomes impossible. In general, the state where no adsorption occurs is a temperature close to the boiling point of the adsorbed molecule. For example, considering the case where paraffinic hydrocarbons such as hexane are adsorbed on the activated carbon surface, the number of hexane molecules adsorbed on the activated carbon surface suddenly decreases from where the boiling point of hexane is exceeded, and the molecules are detached. It becomes like this. However, it can be considered that physical adsorption and chemical adsorption coexist in the case of materials such as water whose hydrogen bonding force cannot be ignored or substances that are biased in electronegativity. However, a temperature of 200 ° C. or higher is required. Even in this case, when a temperature higher than the boiling point is applied, the molecules can be detached and the physical adsorption filter O can be regenerated.
From such a point of view, the filtration performance is not irreversible like the physical filter M and the chemical adsorption filter N described above, and the original performance can be easily recovered by heating. Can be said.

  When the detector 13 displays an instruction signal for replacing the filter unit 2 when the air flow rate is below the reference value, only the filter 2B is replaced. Also, the detector 14 is used in the filter unit 4 when the air flow rate is below the reference, the acidity and alkalinity of the air are out of the reference value, or the integrated air flow is above a certain amount. When a switching signal for switching the filter 4A being switched to another spare filter 4B is displayed, the filter 5 is switched to. Thus, each filter can be replaced according to clogging.

The operation will be described below.
As a filter that performs physical adsorption, the filter unit 4 uses a filter 4A.
The methanol in the cartridge 2A of the filter unit 2 is supplied to the reformer 6 by the fluid pump 5, and the reformer 6 chemically reacts with methanol to generate hydrogen gas. The separator 21 and the fuel electrode 20 of the fuel cell 8 Introduce between.
On the other hand, air that has been subjected to physical filtration and chemical adsorption filtration by the filter 2B of the filter unit 2 is supplied to the filter 4A of the filter unit 4 by the pump 3, and after performing physical adsorption filtration and chemical adsorption filtration by this filter 4A, The fuel cell 8 is supplied between the separator 21 and the air electrode 19.

On the fuel electrode 20 side, the hydrogen gas emits electrons to be protonated, passes through the electrolyte 18 and moves to the air electrode 19 side, and on the air electrode 19 side, the electrons released when the hydrogen gas is protonated. The electromotive force is generated by the chemical reaction with oxygen in the air in response to the supply of.
At this time, if the detector 13 detects that the air flow rate is equal to or lower than the reference flow rate, it is determined that the filter 2B is clogged, and an instruction signal for replacing the filter 2B of the filter unit 2 is sent from the control circuit 16 to the detector 13. Since this is displayed, the filter 2B of the filter unit 2 is replaced. If the detector 18 detects that the air flow rate is less than the reference flow rate, the acidity or alkalinity of the air is outside the reference value, or the integrated air flow rate is more than a certain amount, the control circuit 16 A switching signal for switching the used filter 4A to the spare filter 4B is simultaneously output to the switchers 11 and 12, and the filter 4A is switched to another spare filter 4B.

  After switching to the filter 4B, the filter 4A is heated to a predetermined temperature by the heater 4C, and the gas adsorbed on the physical adsorption filter O of the filter 4C is scattered. When the gas is adsorbed to the physical adsorption filter O of the filter 4B by switching from the filter 4A to the filter 4B by the switching signal from the control circuit 16 to the switching units 11 and 12, the heater 4D is also the same as described above. Heat with to disperse the gas. By doing so, clean air is always supplied to the fuel cell 7. It is desirable to provide a temperature confirmation circuit composed of a thermocouple or the like in order to confirm whether or not the desired temperature is reached when heating. This is because the provision of such a circuit has an effect that enables efficient operation without raising the temperature to an unnecessary heating temperature.

  As described above, according to the embodiment of the present invention, the switch 11 that switches between the filter unit 2 including the physical filter M and the chemical adsorption filter N and the filters 4A and 4B including the physical adsorption filter O is provided. , 12, the filter can be replaced or switched according to the type of substance that causes clogging of each filter. As a result, since clean air is supplied to the fuel cell 7, it is possible to provide a fuel cell driving device that can be always operated without causing clogging.

Next, a modification of the embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 4, in the fuel cell drive device 22 of the modification, the filter unit 2 in the fuel cell drive device 1 is only the physical filter M, and instead of the physical adsorption filter O of the filters 4A and 4B, chemical adsorption filtration. This is the same as in the case of N.
It is effective in places where there are few substances that physically adsorb, such as water such as water vapor and moisture, organic solvents such as toluene, benzine and gasoline, acetate esters, and acrylate esters. Since the physical adsorption filter O is unnecessary, in addition to the effects of the embodiment of the present invention, the cost can be reduced and the apparatus can be downsized.

  In addition, although the physical adsorption filter O was used for filter part 4A, 4B of the physical filter M, the chemical adsorption filter N, and the filter part 4 for the filter 2B of the filter part 2, the chemical adsorption filter O of the filter part 2 was used. Instead, a physical filter M may be used. Further, for example, even when the physical filter M is abnormal and needs to be removed, the chemical adsorption filter N and the physical adsorption filter O are working, so that clean air is supplied to the fuel cell 7. Therefore, the electromotive force of the fuel cell 7 does not decrease. A fuel cell system that supplies hydrogen directly to the fuel cell without using methanol, or an alcohol such as pure methanol, ethanol, or isopropyl alcohol without using methanol may be used.

It is the schematic which shows the fuel cell drive device in embodiment of this invention. The structure of a fuel cell is shown, (A) is a perspective view, (B) is sectional drawing. It is a figure which shows the combination of the filter part used for a fuel cell drive device. It is the schematic which shows the modification of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,22 ... Fuel cell drive device, 2, 4 ... Filter part, 2A ... Cartridge, 2B, 4A, 4B ... Filter, 3 ... Pump, 5 ... Fluid pump, 6 ... Reformer, 7 ... Fuel cell, 8 ... Load resistance, 9 ... current detector, 10 ... exhaust port, 11, 12 ... switch, 16 ... control circuit, 4C, 4D ... heater, 13, 14, 15 ... detector, 17 ... catalyst layer, 18 ... electrolyte, 19 ... Air electrode, 20 ... Fuel electrode, 21 ... Separator

Claims (2)

A fuel cell that generates an electromotive force by a chemical reaction between hydrogen and oxygen generated by a chemical reaction of fuel is used to separate the oxygen that is necessary to always cause the chemical reaction regardless of the external environment. In the fuel cell drive device that supplies stably,
A first filter part having a filter for physically or chemically filtering the air;
A second filter unit having a plurality of filters for physically adsorbing and filtering the air filtered by the filter of the first filter unit;
A switch for switching a filter used in the plurality of second filter units to a spare filter;
The first filter unit is provided between the first filter unit and the second filter unit, detects the flow rate of air passing through the first filter unit, and detects the flow rate of the air when the air flow rate is equal to or less than a reference value. A first detector for displaying an instruction signal to be exchanged;
Switching that is provided at the subsequent stage of the second filter unit and detects the flow rate of air passing through the second filter unit and switches to the preliminary filter of the second filter unit when the air flow rate is below a reference value. A second detector for displaying the signal;
When the flow rate of the air detected by the first detector is below a reference, an instruction signal for exchanging the first filter unit is output to the first detector and detected by the second detector. If the flow rate of the air is below the reference, the acidity and alkalinity of the air are out of the reference values, or the integrated flow rate of the air is above a certain amount, Control means for causing the second detector to output a switching signal for switching the filter used in 1 to the preliminary filter;
A fuel cell drive device comprising: 2. The fuel cell drive device according to claim 1, wherein the plurality of filters of the second filter unit are filters that perform physical adsorption filtration that can be regenerated by heating. 3.

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